DR: Abnormal skin Flashcards
Define abrasion
superficial removal of the epidermis
Define abscess
Localised collection of pus in a cavity formed by necrosis of tissue. Dermal or stratum corneum accumulation of pus
Define acantholysis
Loss of cohesion between cells of living epidermis (especially stratum
spinosum: acanthus = thorn, spine)
Define acanthocyte
Epidermal cell free in vesicle or pustule caused by acantholysis
Define acanthosis
Hyperplasia of stratum spinosum
Define acariasis
Infestation with any mites
Define acral
Pertaining to the distal parts of the body
Define actinic
Referring to the harmful effects of ultraviolet light
Define adnexa
Cutaneous appendages (hair, claws and glands). Plural adnexae
Define allergen
A substance capable of initiating an allergic response
DEfine allergy
hypersensitivity reaction initiated by specific immunological
mechanisms
Define alopecia
Histopathology
Example
Absence of hair in an area where it is normally present
HISTO: various, follicular atrophy or dystrophy if hairgrowth disrupted, may be inflammatory patterns if alopecia is traumatic
EXAMPLE = endocrine usually causes atrophic pattern. FAD cats often lead to traumatic alopecia
Define anagen
Growth phase of hair cycle
Define anaphylaxis
An exaggerated immune response to a foreign protein
Define annular
ring-shaped
Define anthropophilic
With a preference for man; dermatophytes
Define atopy
Strictly ‘strange disease’. Popularly an inherited hypersensitivity state
mediated by reaginic antibody
What is an auriscope
Synonym for ‘otoscope’
Define bulla
Histopathology
Example
A large vesicle or blister (>1cm), contains clear fluid
HISTO: intra or subepidermal separation without marked cellular accumulation, often viral infection or autoimmune disease
EXAMPLE: FMDV, BP
Define calcinosis
Accumulation of calcium crystals in the skin
Define callus
Hypertrophy of the epidermis, especially over pressure points
Define catagen
Transition phase of the hair cycle
Define cellulitis
Used to described chronic, deep bacterial infection of the dermis and
subcutis with a diffuse, rapidly spreading, suppurative response
dissecting along and through tissue planes
Define cerumen
The wax like secretions of the apocrine glands of the ear canal
Define comedo
Plugged (with keratinous debris) and dilated hair follicle, (pl. comedones). = blackheads. devoid of hair
HISTO = follicular keratinisation defects, +/- hair growth arrest
EXAMPLE dogs with Demodex. Also Cushings, Hypothyroidism, primary defects of keratinisation, idiopathic seborrhoea
Define cornification
The maturation process of epidermal cells (syn. keratinisation)
Define crust
Histopathology
Example
Solid accumulation of exudate on the skin surface. serocellular or haemorrhagic
HISTOPATHOLOGY: ulceration or exocytosis of inflammatory cells through epidermis, +/- spongiosis
EXAMPLE: canine scabies
Define cutis
The whole skin
Compare and contrast follicluitis with furunculosis
- FOLLICULITIS = inflammation of a follicle
- FURUNCULOSIS = inflammation and destruction of a follicle. E.g. perianal fistula and/or furunculosis in GSD. Deep pyoderma causing furunculosis.
Define demodicosis
A skin disease associated with infestation with Demodex mites
Define dermatitis
Inflammation of the skin
Define dermatome
Area of skin supplied with afferent nerve fibres by a single dorsal
spinal root also the lateral part of an embryonic somite. In surgery,
instrument for removing thin slices of skin for grafting.
Define dermatomycosis
Fungal disease of the skin (any fungus)
Define dermatophyte
A fungus parasite of skin, hairs or nails of the genera Microsporum,
Trichophyton or Epidermophyton
Define dermatosis
A pathological condition of the skin
Define dyskeratosis
Abnormal, premature or imperfect keratinisation of keratinocytes
Define dysplasia
Abnormality of development. Also alteration in size, shape and
organisation of adult cells
Define dystrophy
Wrong growth
Define ecchymosis
Dermal haemorrhage greater than 1 cm diameter
Define epidermal collarette
Example
A peeling edge of epithelium surrounding an ulcer or erosion. (the footpad of a pustule, a secondary lesion. In dogs, most commonly caused by Staph). I.e. a circular lesion with a peripheral rim of scale. secondary lesion as evolves from pustule
EXAMPLE: canine pyoderma
Define epidermolysis
Degeneration of the epidermal basal layer resulting in separation of
the epidermis from the dermis
Define erosion
Example
Superficial ulcer involving only epidermis and healing without scarring. The dermo-epidermal junction is intact. SECONDARY LESION. e.g. drug eruption
Define erythema
Reddening of the skin caused by congestion of the capillaries
Define excoriation
Histology
Example
linear trauma often with erosions and ulcers caused by self trauma
HISTOLOGY: if associated with pruritius, can expect various patterns of skin inflammation, especially perivascular dermatitis
EXAMPLE: feline FAD
Define exfoliation
The shedding of leaf-like scales or layers
Define fissure
Linear cleavage into epidermis or dermis caused by disease or injury
Define follicular cast
Histopathology
Example
An accumulation of keratin and follicular material that adheres/is compressed to the hair shaft extending above the follicular ostia.
HISTO: follicular keratinisation defect
EXAMPLE Demodecosis, idiopathic seborrhoea, endocrine disease
Define furunculosis
Rupture of hair follicles associated with severe inflammation
Define geophilic
Pertaining to organisms that normally inhabit the soil
Define glabrous
Strictly smooth, referring to hairless skin, popularly relatively hairless
Define granuloma
A circumscribed tissue reaction where the histiocyte is the
predominant cell type
Define gynaecomastia
Enlargement of the male mammary gland
Define hyperhidrosis
Increases sweating
Define hyperkeratosis
An increased thickness of the stratum corneum (sacling, non-living layers).
Define hyperplasia
increase in stratum spinosum thickness (i.e. living layers) - stimulated by inflammatory cytokines, almost irrespective of cause.
Define hypersensitivity
Describes objectively reproducible symptoms or signs initiated by
exposure to a defined stimulus at a dose tolerated by normal persons
Define hypotrichosis
Less than the normal amount of hair
Define intertirginous
Rubbing against each other. Used to refer to areas in which the skin
layers opposed one against the other e.g. axilla
Define intertrigo
Frictional inflammation in poorly ventilated areas e.g. skin folds
Define keratinocyte
Epidermal cell undergoing maturation
Define keratolytic
Promoting loosening or separation of cells of the stratum corneum
Define keratoplastic
Promoting ordered keratinisation of stratum corneum. Term is also
used in a different sense in relation to plastic surgery of the cornea
Define keratosis
A condition of excessive development of horny tissue
Define kerion
A nodular, moist, circumscribed infection of the skin and hair follicles
with fungi or bacteria
Define lentigo
When describing a single lesion - a flat, spot due to increased melanin
deposition and an increased number of melanocytes. Plural is
“lentigenes”.
Define leukoderma
Lack of skin pigmentation
Define leukotrichia
Lack of hair pigmentation
Define lichenification
Histology
Example
A thickening of the superficial layers of the skin characterised by exaggerated crevices. Accentuation of normal skin markings leading to elephant skin appearance. SECONDARY LESION
HISTOLOGY: epidermal hyperplasia and superficial dermal inflammation
EXAMPLE: chronic, poorly controlled allergic diseases
Define macule
Histopathology
Example
Circumscribed change in skin colour less than 1 cm in diameter.
HISTO: erythema or pigment disturbance
EXAMPLE: loss of pigment in vitiligo
Define melanoderma
Inreased skin pigmentation
Define melanotrichia
Abnormal (increased) hair pigmentation
Define miliary
Resembling a millet seed
Define mycetoma
Localized deforming tumour with sinus tracts and ‘grains’ or ‘granules’
of the aetiological agent. 2 distinct groups: actinomycetic mycetomas
associated with bacterial filaments of 1 um diameter or less, and
eumycotic mycetomas (eumycetoma) associated with septate, hyphae
of at least 2-4 um diameter. Diagnosis dependent upon demonstration
of the sinuses and granules. When granule is composed of a pure
population of non-filamentous bacteria, a diagnosis of bacterial
granuloma (‘botryomycosis’) should be made.
Define myxoedema
A localised mycotic or actinomycotic infection of skin characterised by
a nodular lesion with sinus tracts and granules in the exudate.
Define necrolysis
Necrosis of epidermal cells leading to separation or exfoliation of
tissue due to necrosis
Define nevus
A circumscribed developmental defect of the skin
Define nikolsky sign
Ability to dislodge normal looking epidermis by sliding digital
pressure The dermo-epidermal junction is taken out to be able to do this therefore it is a pathological finding.
Define nodule
Histopathology
Example
A circumscribed, solid elevation > 1 cm in diameter that usually extends into the deeper skin layers
HISTOPATHOLOGY: dense accumulation of neoplastic or inflammatory cells in dermis and/or pannniculus
EXAMPLE: MCT, mycobacterial skin infection
Define onychogryphosis
Deformed overgrowth of nails
Define onychomadesis
Complete shedding of nails
Define onychomycosis
Fungal nail infection
Define onychorrhexis
A breakage or brittleness of a nail
What is an otoscope?
Instrument for examining the ear
Define papule
Histopathology
Example
= Solid elevation of skin less than 1 cm diameter (nodule if >1 cm)
- HISTO: dense accumulation of inflammatory cells in superficial and/or deep dermis
- EXAMPLE: flea bite allery
Define parakeratosis
Abnormal cornification, keratinocytes retain nuclei
Define paronchia
Inflammation of the tissue fold around the nail bed
Define patch
Histopathology
Example
A macule more than 1 cm in diameter (a macule is a circumscribed change in skin colour less than 1cm in diameter)
HISTO: erythema or pigment disturbance
EXAMPLE: loss of pigment in vitiligo
Define pediculosis
Infestation with lice
Define petechia
Haemorrhage of less than 1 cm diameter
Define pigmentary incontinence
Release of melanin granules into the superficial dermis
Define plaque
Flat topped swelling more than 1 cm diameter
Define pruritus
Intense and persistent itchiness (note spelling)
Define pseudomycetoma
‘Dermatophyte pseudomycetoma’ is a confusing term used to describe
a form of dermatophytosis this is, amongst veterinary species,
primarily reported in Persian cats with M. canis as the aetiological
agent. ‘Fungal granuloma caused by M. canis’ or ‘granulomatous
dermatitis and panniculitis caused by M. canis’ fit more closely with
the accepted disease nomenclature than ‘pseudomycetoma’.
Define pustule
A small circumscribed elevation of the epidermis filled with pus (c.f. abscess where pus accumulates in the dermis or the subcutaenous tissue).
HISTO: dense accumulation of neutrophils (or eosinophils) within epidermis or superficial dermis
EXAMPLE: canine pyoderma
Define scale
Histopathology
Example
An accumulation of fragments of stratum corneum
HISTOPATHOLOGY: hyperkeratosis, induced by wide arrange of processes
EXAMPLE: idiopathic seborrhoea
Define scar
An area of fibrous tissue that has replaced the damaged dermis or subcutaneous tissue
Define spongiosis
Intercellular oedema in the epidermis
Define telogen
The resting phase of the hair cycle
Define ulcer
Example
A break in the continuity of the epidermis with exposure of the underlying dermis but with intact basement membrane. e.g. BP
Define vesicle
Histopathology
Example
A blister less than 1 cm diameter, contains clear fluid, a circumscribed elevation of the skin
HISTO: intra or subepidermal separation without marked cellular accumulation, often viral infection or autoimmune disease
EXAMPLE: FMDV, BP
Define vitiligo
Depigmentation in focal areas where melanocytes are absent
Define wheal
A sharply demarcated raised lesion caused by dermal oedema. A more extensive wheal is known as angioedema (affects whole body region)
Define zoophilic
Pertaining to organisms adapted to animals
List different ways skin can react
Change of colour Rash Change of thickness Abnormal material on surface Hair loss Defect in integrity Lump or swelling
What are common Ddx for erythematous circles 3 (i.e. points of inflammation expanding outwards)
Staphylococcal erythema
Flea bite hypersensitivity
Fly bites
Ddx - skin change of colour to black 3
- Post-inflammatory/ chronic inflammation - esp. allergic dx & Malassezia dermatitis
- Tanning
- Hormonal
Causes - skin change of colour from black to grey
Loss of melanin from epidermis into dermis. Certain dx with focus on epidermis
Causes - skin change of black to white/ pink
Loss of melanocytes (insult or idiopathic)
What should you decide if you see red skin?
erythema or rash
Define rash
collection of skin lesions - diffuse or confluent (e.g. erythema, papules, pustules, crusted papules/ pustules, colarettes)
Ddx - papules
Staphylococcal pyoderma Flea bite hypersensitivity Scabies Atopic dermatitis Fly-bite hypersensitivity Contact dermatitis
Example of crusted papule
miliary dermatitis
Ddx - pustules
- Staphylococcal pyoderma*
- Demodecosis
- Pemphigus
- Other rare sterile pustular disorders
What is an epidermal collarette the remnant of?
a papule or pustule in Staph pyoderma
What might be seen with epidermal collarettes?
Circular scaling
+/- central alopecia
+/- peripheral erythema
+/- central hyperpigmentation
What is increased epidermal thickness?
lichenification
What is increased dermal thickness?
infiltration with cells or mucin
What is decreased skin thickness caused by? Tx?
Due to atrophy. Tx is steroids.
What abnormal material might be present on the skin surface?
- excessive scale - surface scaling or follicular cast
- exudate - crust
- sweat, lipid
What are the patterns of alopecia?
- diffuse/partial/total
- focal/regional
- multifocal
- symmetrical
Causes of circular hair loss - 3
- staph folliculitis
- demodex
- dermatophytes
Name 5 defects in skin integrity
Fissure Excoriation Erosion Ulcer Draining tracts
Causes of erosions/ ulcers
self-trauma Physical/chemical insult Infection Auto-immune dx • primary, or secondary to vesicles/bullae vasculopathy tumour
What may cause draining tracts?
Process in/under skin ‘trying to get out’
Infection, foreign body, necrosis
